1. Technical Field
The present invention relates to a system for assisting fuel-efficient driving that assists a driver in achieving optimum fuel economy while driving a vehicle.
2. Related Art
Due to the rise in oil prices and environmental concerns, vehicle manufacturers have conducted intensive researches to improve fuel efficiency of vehicles. Vehicle fuel efficiency depends not only on vehicle engine and transmission tuning technologies but also drivers' driving habits, such as a rapid deceleration habit or a rapid braking habit. Accordingly, recently, systems for assisting fuel-efficient driving that can advise drivers to perform fuel-efficient driving by displaying the instantaneous fuel efficiency of vehicles in the form of numerical values or graphs have been provided, as disclosed in, for example, Korean Patent Application Publication No. 2000-25188, Korean Patent No. 444351, and Korean Patent Application Publication No. 2000-25188.
However, the prior art systems provide information about the current instantaneous fuel efficiency of vehicles only in consideration of the characteristics of engines, without considering the power transmission efficiency of transmissions. For example, in the case of automatic transmission vehicles, fuel efficiency is degraded when a downshift occurs due to the increase in the opening of a throttle valve (RPM increases) or a damper clutch is not in a directly coupled state (is OFF), but the prior art systems do not take these into consideration at all.
Also, the prior art systems inform drivers of a fuel-efficient driving speed under constant-speed driving conditions, but do not provide information of acceleration or deceleration criteria for achieving fuel-efficient driving in a current driving state.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.